Poison type

Poison-typePokémon have a toxic quality about them, be it because they produce venom (Ekans and Arbok for example), are poisonous plants (Bulbasaur and Oddish – these are dual Grass-and-Poison types), or have some sort of general toxicity about them (such as Koffing or Grimer). Many Poison-type moves can cause the Poison status effect, which causes the attacked Pokémon to lose hit points each turn. The Toxic or 'badly poisoned' status effect causes the amount of damage done by the poison to double each turn. Some Poison Pokémon are considered to represent a forms of pollution such as Koffing/Weezing (air pollution) and Grimer/Muk (toxic waste). Poison-types are immune to the Poisoned status effect.

Trivia

There has only been one Poison-type gym, which is located in Fuchsia City in Kanto, although on April 12th 2012 it was revealed in CoroCoro that in Black 2 and White 2 there would be a Poison type gym in the renovated Unova.